System and method for processing wireless high definition video data using remainder bytes

ABSTRACT

A method and system for processing high definition video data using remainder bytes is disclosed. In one embodiment, the method includes receiving an information packet having the length of L bytes, wherein L=(M×n×K)+A, and where: M is the depth of an interleaver, n is the number of interleavers, K is an encoding code length and A is the number of remainder bytes with respect to M×n×K bytes, wherein the remainder bytes are located at the end of the information packet, and wherein M×n×K bytes represent M×n codewords. The method further includes converting the A remainder bytes into a plurality of shortened codewords, wherein each of the shortened codewords is shorter in length than each of the M×n codewords. At least one embodiment of the invention provides much lower padding efficiency while improving the decoding performance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) from U.S.Provisional Patent Application No. 60/906,382 filed on Mar. 12, 2007,which is hereby incorporated by reference. This application also relatesto U.S. patent application Ser. No. 11/863,109 entitled “System andmethod for processing high definition video data using a shortened lastcodeword,” which is concurrently filed with this application and isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to wireless transmission of videoinformation, and in particular, to transmission of high definition videoinformation over wireless channels.

2. Description of the Related Technology

With the proliferation of high quality video, an increasing number ofelectronic devices, such as consumer electronic devices, utilize highdefinition (HD) video which can require about 1 Gbps (giga bits persecond) in bandwidth for transmission. As such, when transmitting suchHD video between devices, conventional transmission approaches compressthe HD video to a fraction of its size to lower the requiredtransmission bandwidth. The compressed video is then decompressed forconsumption. However, with each compression and subsequent decompressionof the video data, some data can be lost and the picture quality can bereduced.

The High-Definition Multimedia Interface (HDMI) specification allowstransfer of uncompressed HD signals between devices via a cable. Whileconsumer electronics makers are beginning to offer HDMI-compatibleequipment, there is not yet a suitable wireless (e.g., radio frequency)technology that is capable of transmitting uncompressed HD videosignals. Wireless local area network (WLAN) and similar technologies cansuffer interference issues when several devices, which do not have thebandwidth to carry the uncompressed HD signals, are connected together.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One aspect of the invention provides a method of processing highdefinition video data to be transmitted over a wireless medium, themethod comprising: i) receiving an information packet having the lengthof L (bytes), wherein L=(M×n×K)+A, and where: M is the depth of aninterleaver, n is the number of interleavers, K is an encoding codelength and A is the number of remainder bytes with respect to M×n×Kbytes, wherein the remainder bytes are located at the end of theinformation packet, and wherein M×n×K bytes represent M×n codewords andii) converting the A remainder bytes into a plurality of shortenedcodewords, wherein each of the shortened codewords is shorter in lengththan each of the M×n codewords.

Another aspect of the invention provides a system for processing highdefinition video data to be transmitted over a wireless medium, thesystem comprising: i) a first module configured to receive aninformation packet having the length of L (bytes), wherein L=(M×n×K)+A,and where: M is the depth of an interleaver, n is the number ofinterleavers, K is an encoding code length and A is the number ofremainder bytes with respect to M×n×K bytes, wherein the remainder bytesare located at the end of the information packet, and wherein M×n×Kbytes represent M×n codewords and ii) a second module configured toconvert the A remainder bytes into a plurality of shortened codewords,wherein each of the shortened codewords is shorter in length than eachof the M×n codewords.

Another aspect of the invention provides a method of processing highdefinition video data to be transmitted over a wireless medium, themethod comprising: i) providing at least one outer interleaver, whereineach of the at least one outer interleaver has a depth of M, and whereinthe depth represents the number of columns of each outer interleaver,ii) receiving an information packet having the length of L (bytes),wherein L=(M×n×K)+A, wherein n=0, 1, 2, 3, . . . and n represents thenumber of the at least one outer interleaver, wherein K represents anReed Solomon (RS) code length, wherein A=1, 2, 3, . . . K−1 and Arepresents the number of remainder bytes with respect to M×n×K bytes,wherein the remainder bytes are located at the end of the informationpacket, and wherein M×n×K bytes represent M×n codewords, iii) convertingthe A remainder bytes into four shortened codewords, wherein each of theshortened codewords is shorter in length than each of the M×n codewords,wherein the four shortened codewords comprise a last codeword, andwherein the last codeword is 8 bytes shorter in length than theremaining three shortened codewords, iv) RS encoding the plurality ofshortened codewords based on the RS code length (K); v) adding tail bitsto the last codeword so that the length of the last codeword is the sameas those of the remaining shortened codewords and vi) outer interleavingthe plurality of RS encoded shortened codewords with the tail bitsadded.

Another aspect of the invention provides a system for processing highdefinition video data to be transmitted over a wireless medium, thesystem comprising: i) at least one first outer interleaver, wherein eachof the at least one first outer interleaver has a depth of M, andwherein the depth represents the number of columns of each outerinterleaver, ii) a first module configured to receive an informationpacket having the length of L (bytes), wherein L=(M×n×K)+A, wherein n=0,1, 2, 3, . . . and n represents the number of the at least one firstouter interleaver, wherein K represents an Reed Solomon (RS) codelength, wherein A=1, 2, 3, . . . K−1 and A represents the number ofremainder bytes with respect to M×n×K bytes, wherein the remainder bytesare located at the end of the information packet, and wherein M×n×Kbytes represent M×n codewords, iii) a second module configured toconvert the A remainder bytes into four shortened codewords, whereineach of the shortened codewords is shorter in length than each of theM×n codewords, wherein the four shortened codewords comprise a lastcodeword, and wherein the last codeword is 8 bytes shorter in lengththan the remaining three shortened codewords, iv) an RS encoderconfigured to RS encode the plurality of shortened codewords based onthe RS code length (K), v) a third module configured to add tail bits tothe last codeword so that the length of the last codeword is the same asthose of the remaining shortened codewords and vi) a second outerinterleaver configured to outer interleave the plurality of RS encodedshortened codewords with the tail bits added.

Still another aspect of the invention provides a system for processinghigh definition video data to be transmitted over a wireless medium, thesystem comprising: i) means for receiving an information packet havingthe length of L (bytes), wherein L=(M×n×K)+A, and where: M is the depthof an interleaver, n is the number of interleavers, K is an encodingcode length and A is the number of remainder bytes with respect to M×n×Kbytes, wherein the remainder bytes are located at the end of theinformation packet, and wherein M×n×K bytes represent M×n codewords andii) means for converting the A remainder bytes into a plurality ofshortened codewords, wherein each of the shortened codewords is shorterin length than each of the M×n codewords.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a wireless network thatimplements uncompressed HD video transmission between wireless devicesaccording to one embodiment.

FIG. 2 is a functional block diagram of an example communication systemfor transmission of uncompressed HD video over a wireless medium,according to one embodiment.

FIG. 3 illustrates an exemplary HD video data transmitter system 300according to one embodiment of the invention.

FIG. 4 illustrates a conceptual diagram showing an encoding procedure ofa HD video data transmitter for a wireless video area network (WVAN)according to one embodiment of the invention.

FIG. 5 is an exemplary flowchart for the encoding procedure according toone embodiment of the invention.

FIG. 6 illustrates a conceptual diagram showing an encoding procedure ofa HD video data transmitter for a WVAN according to another embodimentof the invention.

FIG. 7 is an exemplary flowchart for the encoding procedure according toone embodiment of the invention.

FIG. 8 illustrates a conceptual diagram showing an encoding procedure ofa HD video data transmitter for a WVAN according to another embodimentof the invention.

FIG. 9 is an exemplary flowchart for the encoding procedure according toone embodiment of the invention.

FIG. 10 illustrates a conceptual diagram showing an encoding procedureof a HD video data transmitter for a WVAN according to anotherembodiment of the invention.

FIG. 11 is an exemplary flowchart for the encoding procedure accordingto another embodiment of the invention.

FIG. 12A illustrates a conceptual drawing of an interleaver for theremainder codewords according to one embodiment.

FIG. 12B illustrates a conceptual drawing of an interleaver for theremainder codewords according to another embodiment.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Certain embodiments provide a method and system for transmission ofuncompressed HD video information from a sender to a receiver overwireless channels.

Example implementations of the embodiments in a wireless high definition(HD) audio/video (A/V) system will now be described. FIG. 1 shows afunctional block diagram of a wireless network 100 that implementsuncompressed HD video transmission between A/V devices such as an A/Vdevice coordinator and A/V stations, according to certain embodiments.In other embodiments, one or more of the devices can be a computer, suchas a personal computer (PC). The network 100 includes a devicecoordinator 112 and multiple A/V stations 114 (e.g., Device 1, Device 2,. . . , Device N). The A/V stations 114 utilize a low-rate (LR) wirelesschannel 116 (dashed lines in FIG. 1), and may use a high-rate (HR)channel 118 (heavy solid lines in FIG. 1), for communication between anyof the devices. The device coordinator 112 uses a low-rate channel 116and a high-rate wireless channel 118, for communication with thestations 114.

Each station 114 uses the low-rate channel 116 for communications withother stations 114. The high-rate channel 118 supports single directionunicast transmission over directional beams established by beamforming,with e.g., multi-giga bps bandwidth, to support uncompressed HD videotransmission. For example, a set-top box can transmit uncompressed videoto a HD television (HDTV) over the high-rate channel 118. The low-ratechannel 116 can support bi-directional transmission, e.g., with up to 40Mbps throughput in certain embodiments. The low-rate channel 116 ismainly used to transmit control frames such as acknowledgement (ACK)frames. For example, the low-rate channel 116 can transmit anacknowledgement from the HDTV to the set-top box. It is also possiblethat some low-rate data like audio and compressed video can betransmitted on the low-rate channel between two devices directly. Timedivision duplexing (TDD) is applied to the high-rate and low-ratechannel. At any one time, the low-rate and high-rate channels cannot beused in parallel for transmission, in certain embodiments. Beamformingtechnology can be used in both low-rate and high-rate channels. Thelow-rate channels can also support omni-directional transmissions.

In one example, the device coordinator 112 is a receiver of videoinformation (hereinafter “receiver 112”), and the station 114 is asender of the video information (hereinafter “sender 114”). For example,the receiver 112 can be a sink of video and/or audio data implemented,such as, in an HDTV set in a home wireless network environment which isa type of WLAN. In another embodiment, the receiver 112 may be aprojector. The sender 114 can be a source of uncompressed video oraudio. Examples of the sender 114 include a set-top box, a DVD player orrecorder, digital camera, camcorder, other computing device (e.g.,laptop, desktop, PDA, etc.) and so forth.

FIG. 2 illustrates a functional block diagram of an examplecommunication system 200. The system 200 includes a wireless transmitter202 and wireless receiver 204. The transmitter 202 includes a physical(PHY) layer 206, a media access control (MAC) layer 208 and anapplication layer 210. Similarly, the receiver 204 includes a PHY layer214, a MAC layer 216, and an application layer 218. The PHY layersprovide wireless communication between the transmitter 202 and thereceiver 204 via one or more antennas through a wireless medium 201.

The application layer 210 of the transmitter 202 includes an A/Vpre-processing module 211 and an audio video control (AV/C) module 212.The A/V pre-processing module 211 can perform pre-processing of theaudio/video such as partitioning of uncompressed video. The AV/C module212 provides a standard way to exchange A/V capability information.Before a connection begins, the AV/C module negotiates the A/V formatsto be used, and when the need for the connection is completed, AV/Ccommands are used to stop the connection.

In the transmitter 202, the PHY layer 206 includes a low-rate (LR)channel 203 and a high rate (HR) channel 205 that are used tocommunicate with the MAC layer 208 and with a radio frequency (RF)module 207. In certain embodiments, the MAC layer 208 can include apacketization module (not shown). The PHY/MAC layers of the transmitter202 add PHY and MAC headers to packets and transmit the packets to thereceiver 204 over the wireless channel 201.

In the wireless receiver 204, the PHY/MAC layers 214, 216 process thereceived packets. The PHY layer 214 includes a RF module 213 connectedto the one or more antennas. A LR channel 215 and a HR channel 217 areused to communicate with the MAC layer 216 and with the RF module 213.The application layer 218 of the receiver 204 includes an A/Vpost-processing module 219 and an AV/C module 220. The module 219 canperform an inverse processing method of the module 211 to regenerate theuncompressed video, for example. The AV/C module 220 operates in acomplementary way with the AV/C module 212 of the transmitter 202.

In frame based bursty communication systems, information bytes aregenerally grouped in packets/frames before transmission. Packetizationof the information bytes is generally straightforward. However,non-negligible efficiency loss could occur if the packetization is notdone properly. This is especially true toward the end of eachframe/packet.

In a typical HD video data transmitter for a wireless video area network(WVAN), the packetization task toward the end of the packet is generallynon-trivial as the transmitter generally uses Reed Solomon (RS) codesfollowed by an outer block interleaver code and a parallel of multipleconvolutional codes in an orthogonal frequency division multiplexing(OFDM) setup.

In one embodiment, in order to ensure that an integer number of OFDMsymbols are created, the high rate physical layer (HRP) will addadditional bits to the bit stream, generally called stuff bits, prior toperforming any operations on the incoming data. Stuff bits are typicallyset to zero prior to adding them to the end of the bit stream. The HRPgenerally adds the minimum number of stuff bits necessary to create aninteger number of OFDM symbols for the combination of the physical layerheader field, medium access control (MAC) header field and header checksequence (HCS) field. These additional bits are typically discarded bythe receiver upon reception. In addition, the HRP generally adds theminimum number of stuff bits necessary to create an integer number ofOFDM symbols for each of the subpackets that end on a HRP mode changeand for the last subpacket. These additional bits are not included inthe calculation of the MAC protocol data unit (MPDU) length field andare discarded by the receiver upon reception.

In the IEEE 802.11n standard, the encoding procedure is defined for alow density parity check (LDPC) coded OFDM system. The design is to meetboth the LDPC codeword boundary and the OFDM symbol boundary, whileimproving the coding performance and padding efficiency. In a wirelessHD video data transmitter, more constraints may exist compared with the802.11n case, because the wireless transmitter may need to meet the RScodeword boundary, the block outer-interleaver boundary, the padding oftail bits for convolutional codes after the outer interleaver, and theOFDM symbol boundary. Therefore, the design is generally morecomplicated in the WVAN system.

In the digital video broadcast-terrestrial (DVB-T) standard, where aconcatenated RS code with convolutional codes is used, the encodingprocedure is also much simpler than the wireless HD transmitter becausea convolutional outer interleaver is used in the DVB-T system instead ofa block interleaver, as well as only one convolutional code is used.

In a typical WVAN system targeting multi-giga bps video/datacommunications over a short range, information bytes are first equallydivided into two branches, with a possibly different modulation andcoding method used for each branch, in order to accommodate the unequalerror protection concept where the data of the two branches receive adifferent level of error protection.

FIG. 3 illustrates an exemplary HD video data transmitter system 300according to one embodiment of the invention. It is appreciated thatcertain elements of the system 300 may be omitted or combined to otherelements of the system 300. In another embodiment, a certain element maybe broken into a plurality of sub-elements. Also, the order of certainelements in the system 300 may change. In addition, certain elements,not shown in FIG. 3, may be added to the system 300. Furthermore,specific features of each element shown in FIG. 3 are merely examplesand many other modifications may also be possible. In one embodiment,all of the elements of the FIG. 3 system 300 belong to the PHY layer 206(see FIG. 2). In one embodiment, most significant bits (MSBs) and leastsignificant bits (LSBs) of data are equally protected (EEP) with respectto error codings. In another embodiment, MSBs and LSBs are unequallyprotected (UEP) with respect to error codings. In one embodiment, all ofthe elements of the FIG. 3 system 300 can be embodied by either softwareor hardware or a combination.

In one embodiment, instead of using RS encoders 304 and 306, other outerencoders such as a Bose, Ray-Chaudhuri, Hocquenghem (BCH) encoder can bealso used. In one embodiment, instead of using one or more convolutionalencoders 312, other inner encoders such as a linear block encoder can bealso used. In one embodiment, each of the convolutional encoders 312 mayinclude a plurality of parallel convolutional encoders which encode aplurality of incoming data bits, respectively. In this embodiment, thesystem 300 may further include at least one parser (not shown),generally located between each of outer interleavers 308, 310 and eachof the convolutional encoders 312, which parses the outer interleaveddata bits to a corresponding one of the convolutional encoders 312.However, for convenience, the FIG. 3 system will be described based onRS encoders and convolutional encoders.

In another embodiment, it is also possible to have a single RS (orouter) encoder and a single outer interleaver instead of using a pair ofthose elements 304, 306 and 308, 310. In another embodiment, it is alsopossible to have more than two of the RS encoders, outer interleavers,convolutional encoders and multiplexers.

Referring to FIG. 3, the system 300 receives an information packet froma MAC layer (see 208 in FIG. 2). In one embodiment, a scrambler 302scrambles the received packet and outputs most significant bits (MSBs)and least significant bits (LSBs) to the first and second RS encoders304, 306, respectively.

The RS encoders 304, 306 encode the MSBs and LSBs, respectively. Thefirst and second outer interleavers 308, 310 outer interleave the RSencoded data, respectively. In one embodiment, each of the outerinterleavers 308, 310 is a block interleaver or a convolutionalinterleaver. In another embodiment, other forms of interleavers are alsopossible.

The convolutional encoder(s) 312 perform(s) convolutional encoding andpuncturing on the outer interleaved data, and output(s), for example,four bits of data, corresponding to the MSBs and LSBs, respectively, toa multiplexer 314. In one embodiment, the convolutional encoders 312 mayinclude a plurality of convolutional (or inner) encoders some of whichare for the MSBs and the others of which are for the LSBs. In thisembodiment, the number of convolutional encoders for MSB data may be thesame (e.g., 4 and 4) as that of inner encoders for LSB data. In anotherembodiment, the number of convolutional encoders for MSB data may bedifferent (e.g., 6 and 2) from that of convolutional encoders for LSBdata. In one embodiment, each of the convolutional encoders may provideequal error protection (EEP) for all incoming data bits. In anotherembodiment, the convolutional encoders may provide unequal errorprotection (UEP) for all incoming data bits.

The multiplexer 314 multiplexes the bit streams output from theconvolutional encoders 312 to a multiplexed data stream to be providedto a bit interleaver 316. The bit interleaver 316 bit-interleaves themultiplexed data stream. A symbol mapper 318 performs symbol mappingsuch as quadrature amplitude modulation (QAM) mapping on thebit-interleaved data. A pilot/DC null insert unit 320 and a toneinterleaver 322 perform pilot/DC null inserting and tone interleaving,respectively. An inverse Fourier fast transform (IFFT) unit 324 performsIFFT processing on the output of the tone interleaver 322. A guardinterval unit 326 and a symbol shaping unit 328 perform guard intervaland symbol shaping for the IFFT processed data, sequentially. In oneembodiment, the IFFT unit 324 and the guard interval unit 326 togetherperform orthogonal frequency division multiplexing (OFDM) modulation. Anupconversion unit 330 performs upconversion on the output of the symbolshaping unit 328 before transmitting the data packet to a HD video datareceiver over the wireless channel 201 (see FIG. 2). In one embodiment,the HD video data receiver may include a single convolutional decoder ora plurality of convolutional decoders corresponding to the convolutionalencoder(s) of the transmitter system 300.

In one embodiment, as shown in FIG. 3, each branch is first encoded byan RS code (224, 216, t=4), followed by a block interleaver 308, 310 ofsize, for example, 4×224 (depth four outer interleaver). For eachbranch, the interleaved output is parsed into, for example, M=4 parallelconvolutional encoders 312. For each convolutional code, a certainlength of all-zero tail bits are inserted into the output of the outerinterleaver 308, 310 by further shortening of the RS code. Insertion ofthe tail bits is to simplify the decoding task of convolutional codes atthe receiver side.

Further describing inserting tail bits based on one embodiment, theinformation symbols are divided into equal-sized units, with each unitcontaining equal 4×K information symbols, so that each unit after RSencoding matches with the interleaver size. In this embodiment, theending unit (or the last unit) would have 0≧q≦4×K symbols available,while q may take arbitrary value in between.

In one embodiment, the ending packet contains 4×(K−M) informationsymbols, with each symbol being, for example, 8-bit long. Additionalzeros may be added to the data packets (with the tail-bit-zeros forconvolutional codes to be added later), which will lower the overallefficiency. Since each unit is of 4K symbols (or 32K bits), eachsubpacket (approximately 50 μs long) may contain up to only 10 units for1080i (1080 interlaced scan). Thus, in order to meet the boundaries ofthe RS encoder and block interleaver, such a packetization leads to anaverage efficiency reduction of about 5% and a maximum efficiencyreduction of about 10% for 1080i.

One embodiment of the invention provides a systematic way to dopacketization of the information bits for wireless HD videocommunication systems and provides much higher padding efficiency (i.e.,much more efficient padding) while improving the decoding performance.

Summarizing the operation of the FIG. 3 system, data is first RS encodedand then outer interleaved using, for example, a depth four blockinterleaver. The interleaved data is parsed into, for example, 8parallel convolutional encoders where each convolutional encoderrequires tail bits to terminate. The convolutional encoded data bits aremultiplexed together, interleaved and mapped to QAM constellation forOFDM modulation. In one embodiment, the transmitted data bits meet thefollowing: (1) integer number of RS codeword, (2) integer number ofouter interleaver size, (3) tail bits need to be inserted before CCencoding and (4) additional padding bits are needed to ensure integernumber of OFDM symbols.

For convenience, four encoding schemes shown in FIGS. 4-11, which meetthe above four requirements, will be described. Typically, as additionalpadding bits are inserted and transmitted, the more padding bits areadded, the lower the transmission efficiency. Therefore, at least oneembodiment maximizes the efficiency while maintaining the codingperformance and the simplicity of the system. It is appreciated that thefour schemes are merely exemplary and other schemes may also bepossible. In one embodiment, the four schemes can be implemented withthe FIG. 3 system.

Scheme 1

FIG. 4 illustrates a conceptual diagram showing an encoding procedure500 (see FIG. 5) of a HD video data transmitter for a wireless videoarea network (WVAN) according to one embodiment of the invention. FIG. 5is an exemplary flowchart for the encoding procedure 500 according toone embodiment of the invention.

In one embodiment, the encoding procedure 500 is implemented in aconventional programming language, such as C or C++ or another suitableprogramming language. In one embodiment of the invention, the program isstored on a computer accessible storage medium at a HD video datatransmitter for a WVAN, for example, a device coordinator 112 or devices(1−N) 114 as shown in FIG. 1. In another embodiment, the program can bestored in other system locations so long as it can perform thetransmitting procedure 500 according to embodiments of the invention.The storage medium may comprise any of a variety of technologies forstoring information. In one embodiment, the storage medium comprises arandom access memory (RAM), hard disks, floppy disks, digital videodevices, compact discs, video discs, and/or other optical storagemediums, etc. In another embodiment, at least one of the devicecoordinator 112 and devices (1−N) 114 comprises a processor (not shown)configured to or programmed to perform the transmitting procedure 900.The program may be stored in the processor or a memory of thecoordinator 112 and/or the devices (1−N) 114. In various embodiments,the processor may have a configuration based on, for example, i) anadvanced RISC machine (ARM) microcontroller, ii) Intel Corporation'smicroprocessors (e.g., the Pentium family microprocessors) and iii)Microsoft Corporation's Windows operating systems (e.g., Windows 95,Windows 98, Windows 2000 or Windows NT). In one embodiment, theprocessor is implemented with a variety of computer platforms using asingle chip or multichip microprocessors, digital signal processors,embedded microprocessors, microcontrollers, etc. In another embodiment,the processor is implemented with a wide range of operating systems suchas Unix, Linux, Microsoft DOS, Microsoft Windows 2000/9x/ME/XP,Macintosh OS, OS/2 and the like. In another embodiment, the transmittingprocedure 500 can be implemented with an embedded software. Depending onthe embodiments, additional states may be added, others removed, or theorder of the states changes in FIG. 5. The description of this paragraphapplies to the remaining schemes shown in FIGS. 6-11.

Referring to FIGS. 3-5, the operation of the scheme 1 encoding procedurewill be described in greater detail. For convenience, it is assumed thatan outer encoder is an RS encoder and an inner encoder is aconvolutional encoder. It is appreciated that other outer encoders orother inner encoders (for example as discussed above) may also be used.The same applies to the remaining schemes 2-4 illustrated in FIGS. 6-11.

In one embodiment, scheme 1 provides the most straightforward encodingprocedure among the four schemes. In one embodiment, the system 300receives L information bytes 400 from the MAC layer (502). Theinformation bytes 400 include main codewords 402 and remainder codewords404. The remainder codewords 404 are less than, e.g., four codewords andlocated at the end of the information packet 400. Each block of theinformation bytes 400 represents a codeword having the length of, e.g.,1K bytes, where K=1024. This applies to the remaining schemes shown inFIGS. 6-11.

The system 300 RS encodes the information bytes 402 with the RS code of(N, K, t), where K is the number of information bytes, N is the numberof bytes in the codeword, and t is correction capability (504). Afterthe RS encoding, 2t (e.g., 8) bytes of parity bits 408 are added percodeword to form the size N byte codewords as shown in FIG. 4. The lastcodeword 412 c of the three remainder codewords 412 a-412 c is shortenedto, for example, (m+2t, m), wherein m=mod(L, K) (506). This is to reducethe transmission time, which will further improve the performance of thelast codeword 412 c. In one embodiment, the shortening of the lastcodeword 412 c may be performed by at least one of the RS encoders 304,306. In another embodiment, the shortening of the last codeword 412 cmay be performed by another element of the FIG. 3 system or a separateelement which is not shown in FIG. 3. This applies to the remainingschemes shown in FIGS. 6-11.

In one embodiment, certain length of zeros 416 are padded to the RSencoded codewords to, for example, ceil (L/4K)×4N (508). In oneembodiment, each of the outer interleavers has a depth of 4 (the numberof columns of each outer interleaver) as shown in FIG. 4. The outerinterleaver may have the size of 4×224 bytes. The zero padding is toform a set of four codewords 414 in order to meet the depth four outerinterleaver requirement. In one embodiment, the zero padding may beperformed by at least one of the outer interleavers 308, 310. In anotherembodiment, the zero padding may be performed by another element of theFIG. 3 system or a separate element which is not shown in FIG. 3. Thisapplies to the remaining schemes shown in FIGS. 6-11.

The RS encoded codewords 410 and zero-padded codewords 414 are outerinterleaved and parsed (510). In this embodiment, each outer interleaverperforms outer interleaving on a set of four codewords 410 and 414. Thisapplies to the remaining schemes shown in FIGS. 6-11.

Tail bits 420 are further inserted to the outer interleaved data andconvolutional encoding is performed for the data having the tail bits420 thereafter (512). Padding tail bits 420 is to terminate theconvolutional codes such that decoding at the receive side is properlyperformed. In one embodiment, 1 byte of tail bits (e.g., 1 byte ofzeros) is added per a convolutional encoder. For example, for 8convolutional encoders, 8 bytes of tail bits are added. In oneembodiment, padding tail bits 420 in state 512 may be performed by atleast one of the outer interleavers 308, 310. In another embodiment, thepadding of the tail bits may be performed by another element of the FIG.3 system or a separate element which is not shown in FIG. 3. Thisapplies to the remaining schemes shown in FIGS. 6-11.

More scrambled zeros 424 are inserted to the convolutional coded bytesin order to provide an integer number of OFDM symbols (514).Multiplexing of the data having the scrambled zeros 424 is performedthereafter. In one embodiment, padding scrambled zeros 424 may beperformed by the multiplexer 314. In another embodiment, paddingscrambled zeros 424 may be performed by another element of the FIG. 3system or a separate element which is not shown in FIG. 3. This appliesto the remaining schemes shown in FIGS. 6-11. Thereafter, the rest ofthe OFDM transmission procedure is performed by the remaining elements316-330 of the FIG. 3 system (516). This applies to the remainingschemes shown in FIGS. 6-11

Scheme 2

FIG. 6 illustrates a conceptual diagram showing an encoding procedure600 (see FIG. 7) of a HD video data transmitter for a WVAN according toanother embodiment of the invention. FIG. 7 is an exemplary flowchartfor the encoding procedure 600 according to one embodiment of theinvention. Referring to FIGS. 3 and 6-7, the operation of the scheme 2encoding procedure will be described in greater detail.

Scheme 1 provides relatively a straightforward scheme. However, thepadding efficiency may be low. Scheme 2 provides some improvement ontransmission efficiency over scheme 1. The system 300 receives Linformation bytes 520 from the MAC layer (560). The information bytes520 may include main codewords 522 and remainder codewords 524.

The system 300 RS encodes the information bytes 520 with the RS code of(N, K, t), where K is the number of information bytes, N is the numberof bytes in the codeword, and t is correction capability (562). Afterthe RS encoding, 2t parity bytes 526 are added to form the size N bytecodewords as shown in FIG. 6.

The last codeword 528 (case 1) or 532 (case 2) of the RS encodedremainder codewords is shortened to, for example, (m+2t, m), whereinm=mod(L, K) (564). It is determined whether mod(L, 4K) for the lastcodeword 532 is greater than 4K−8 (566). If it is greater than 4K−8(case 1), partial tail bits 538, for example, less than 8 bytes, areinserted into the RS encoded codewords to form a set of four codewords536 which meets the depth four outer interleaver requirement (568). TheRS encoded codewords 536 with the partial tail bits 538 added are outerinterleaved and parsed (570). Additional tail bits 548, for example, 8bytes minus the number of the partial tail bits, are added to the outerinterleaved data such that total tail bits added are 8 bytes (572).Convolutional encoding is performed for the outer interleaved datahaving the tail bits (partial tail bits 538+additional tail bits 548)thereafter (572).

If it is determined in state 566 whether mod(L, 4K) for the lastcodeword 532 is not greater than 4K−8 (case 2), entire tail bits 544(e.g., 8 bytes) are added to the RS encoded codewords (574). Thereafter,certain length of zeros 542 are padded to the RS encoded codewords toform a set of four codewords 540 which meets the depth four outerinterleaver requirement (576). In one embodiment, padding tail bits 538and 544, and padding zeros 542 may be performed by at least one of theouter interleavers 308, 310. In another embodiment, the padding of thetail bits 538, 544 and zeros 542 may be performed by another element ofthe FIG. 3 system or a separate element which is not shown in FIG. 3.The RS encoded codewords 540, with the tail bits 544 and zeros 542added, are outer interleaved, parsed and convolutional encoded (578). Incase 2, since the entire tail bits 544 have been added in state 574,additional tail bits may not need to be added unlike case 1 (see states568 and 572).

Scrambled zeros 550 are inserted to the convolutional coded bytes inorder to provide an integer number of OFDM symbols (580). Multiplexingof the data having the scrambled zeros 550 is performed thereafter. Instate 582, the rest of the OFDM transmission procedure is performed.

Scheme 3

FIG. 8 illustrates a conceptual diagram showing an encoding procedure700 (see FIG. 9) of a HD video data transmitter for a WVAN according toanother embodiment of the invention. FIG. 9 is an exemplary flowchartfor the encoding procedure 700 according to one embodiment of theinvention. Referring to FIGS. 3 and 8-9, the operation of the scheme 3encoding procedure will be described in greater detail.

The schemes 1 and 2 keep the size of the outer interleaver and pad zerosin different ways. However, due to the relatively large size of theouter interleaver (e.g., 4×224 bytes), the efficiency may be limited.Scheme 3 may further improve the efficiency and the RS code performanceover the schemes 1 and 2. In one embodiment, in scheme 3, instead ofshortening only the last codeword, all of the last four codewords areshortened, which can evenly improve the RS performance, at the same timeenable the usage of a shortened outer interleaver.

Referring to FIGS. 3 and 8-9, the operation of scheme 3 encodingprocedure will be described in greater detail. The system 300 receives Linformation bytes 601 from the MAC layer (702). The information bytes601 may include main codewords 602 and remainder codewords 604. Thesystem 300 calculates the value of “floor(L/4K)×4K”, where K representsan RS code length (704). For convenience, it is assumed that L=4nK+A(bytes), wherein n=0, 1, 2, 3, . . . and n represents the number ofouter interleavers, wherein A=1, 2, 3, . . . K−1 and A represents thenumber of remainder bytes with respect to 4nK bytes. 4nK bytes represent4n codewords. Each outer interleaver performs outer interleaving on aset of four codewords 606. Each codeword includes 2t parity bytes (e.g.,8 bytes) 608.

State 704 separates encoding processing for the first 4nK bytes fromencoding processing for the remainder bytes (A). The first 4nKinformation bytes are RS encoded with, for example, an RS code (N, K,t), wherein t is error correction capability (bytes) and N=K+2t (706).The RS encoded data is outer interleaved, parsed and convolutionalencoded (708).

With regard to the remainder bytes (A), the system 300 evenlydistributes the remainder bytes (A=L′=L−floor (L/4K)×4K) to four RScodewords 610 a-610 d, where the first three RS codes 610 a-610 c haveK1 information bytes and the last RS codeword 610 d has K2 informationbytes (710). In one embodiment, K1 is obtained using the equation “ceil(L′/4)” and K2 is obtained using the equation “L′−3×ceil (L′/4).” Thefour codewords (610 a-610 d) are RS encoded and shortened with an RScode (K1+2t, K1, t) for the first three codewords (610 a-610 c) and anRS code (K2+2t, K2, t) for the last codeword 610 d (712). In oneembodiment, states 704, 710 and 712 may be performed by at least one ofthe RS encoders 304, 306. In another embodiment, states 704, 710 and 712may be performed by another element of the FIG. 3 system or a separateelement which is not shown in FIG. 3.

If needed to meet the outer encoder size requirement, a certain lengthof zeros (e.g., 1-3 bytes) may be padded to the last codeword 610 d(714). The RS encoded data is outer interleaved using a shortened outerinterleaver with the size of 4×(K1+2t) (714).

In one embodiment, the system 300 adds tail bits 615 (e.g., 4×8 bytesfor the four codewords) to the data which has been outer interleaved instates 708 and 714 in order to terminate convolutional codes, andperforms convolutional encoding on the outer interleaved data as shownin FIG. 8 (716). In one embodiment, the adding of the tail bits 615 maybe performed by an element other than the outer interleavers 308, 310.In another embodiment, the adding of the tail bits 615 may be performedby the outer interleavers 308, 310 after the outer interleaving iscomplete.

In one embodiment, additional zeros 618 may be added to theconvolutional encoded data to satisfy the integer number requirement ofOFDM symbols before multiplexing (718). Thereafter, the rest of the OFDMtransmission procedures is performed (720).

In one embodiment, as the RS encoders are shortened in size with respectto the remainder codewords, so is the outer interleaver for theremainder codewords. For example, if the number of the remainder bytes604 is 32 bytes, K1=K2=8 using the above equations, thus each codewordwould have 8 bytes and 8 parity bytes. This can be implemented with anouter interleaver having the size of 4×(K1+2t)=4×(8+8)=4×16 bytes, whichprovides a significantly higher efficiency compared to the outerinterleaver having the size of 4×224 bytes.

As another example, if the number of the remainder bytes 604 is 23bytes, K1=6 and K2=5 using the above equations. In this example, onebyte of zeros is added to the last codeword and each codeword would have6 bytes and 8 parity bytes. This can be implemented with an outerinterleaver having the size of 4×(K1+2t))=4×(6+8)=4×14 bytes, whichprovides a significantly higher efficiency compared to the outerinterleaver having the size of 4×224 bytes.

Scheme 4

FIG. 10 illustrates a conceptual diagram showing an encoding procedure900 (see FIG. 11) of a HD video data transmitter for a WVAN according toanother embodiment of the invention. FIG. 11 is an exemplary flowchartfor the encoding procedure 900 according to another embodiment of theinvention. Referring to FIGS. 3 and 10-11, the operation of the scheme 4encoding procedure will be described in greater detail. States 902-908of FIG. 11 are substantially the same as states 702-708 of FIG. 9.Furthermore, states 920-922 of FIG. 11 are substantially the same asstates 718 and 720 of FIG. 9.

The system 300 determines the value of “L′=L−floor(L/4K)×4K”, where Krepresents an RS code length (910). This state is also substantially thesame as part of state 704 of FIG. 9. L′ 802 represents remainder bytesor the total information bytes for the last interleaver block.

The system 300 determines an RS code for the last RS codeword byte K2(816), for example, using the equation: K2=max (floor ((L′−24)/4), 0)(912). In state 914, the system 300 evenly distributes the (L′−K2)information bytes to the rest of three RS codewords 812-816, where K11is for the first two codewords 812, 814 and K12 is for the thirdcodeword 816. In one embodiment, K11 is obtained by using the equation“K11=ceil ((L′−K2)/3)” and K12 is obtained by using the equation“K12=floor ((L′−K2)/3).”

The first two codewords 812, 814 are encoded with, for example, an RScode (K11+2t, K11, t) and the third codeword 816 is encoded with, forexample, an RS code (K12+2t, K11, t) (916). The last codeword 818 isencoded with, for example, an RS code (K2+2t, K2, t) (916). Thereafter,if needed, tail bits 820 may be added to the last codeword (818) inorder to meet the size requirement of the RS encoder (916).

In order to meet the size requirement of the outer interleaver, thesystem 300 may add zero bytes to the outer interleaver and outerinterleave the RS encoded data using a shortened outer interleaver withthe size of 4×(K11+2t) (918). Thereafter, parsing is performed to parsethe outer interleaved data to convolutional encoders. In one embodiment,states 904 and 910-914 may be performed by at least one of the RSencoders 304, 306. In another embodiment, states 904 and 910-914 may beperformed by another element of the FIG. 3 system or a separate elementwhich is not shown in FIG. 3.

In this scheme 4, the remainder bytes 802 are converted into fourshortened codewords 812-818, where the last codeword 818 is, forexample, eight bytes shorter than the remaining codewords 812-816 asshown in FIG. 10. For example, if L′=32, then K2=2 for the lastcodeword, and K1 (=K11=K12)=10 for the first three codewords in thedepth four outer interleaver. So, the difference between K2 and K1 is 8bytes. 8 bytes of tail bits are added to the last codeword 818 and 8bytes of parity bits are added to each of the first to third codewords812-816. In this example, the shortened outer interleaver would have thesize of 4×(K11+2t)=4×(10+8)=4×18 bytes which provides a significantlyhigher efficiency compared to the outer interleaver having the size of4×224 bytes.

The procedure 900 will be further explained with reference to FIG. 12A.FIG. 12A illustrates a conceptual drawing of an interleaver for theremainder codewords according to one embodiment. It is assumed that thenumber (L′) of the remainder codewords is 23 bytes. In state 912,K2=max(floor((L′−24)/4), 0)=max(floor((23−24)/4), 0)=0. In state 914,K11=ceil((L′−K2)/3=Ceil(23−0)/3=8. Also,K12=floor((L′−K2)/3=floor(23−0)/3=7. The first to third (information)codewords are 8, 8 and 7, respectively, as shown in FIG. 12A. The fourthcodeword is 0 as shown in FIG. 12A. In state 916, 8 bytes of tail bitsare added to the fourth codeword as shown in FIG. 12A (state 916). Instate 918, 1 byte of zeros is padded to the third codeword and 8 bytesof zeros are padded to the fourth codeword as shown in FIG. 12A (state918). In this example, the shortened outer interleaver has the size of4×16 bytes as shown in FIG. 12A which provides a significantly higherefficiency compared to the outer interleaver having the size of 4×224bytes.

Alternative Embodiment Modified Version of Scheme 4

In another embodiment, the information bytes are padded to multiple offour instead of using the ceil/floor operation to calculate K11 and K12as shown in FIG. 12B. FIG. 12B illustrates a conceptual drawing of aninterleaver for the remainder codewords according to another embodiment.In this embodiment, the encoding can be described as following:

Zeros are padded to the L1 information bytes to obtainL2=max{(depth−1)×M, ceil(L1/depth)×depth}. Assuming that L1=23 bytes anddepth=4 and M=8, L2=max{(depth−1)×M, ceil(L1/depth)×depth}=max{(4−1)×8,ceil(23/4)×4}=max {24,20}=24.

The length (K2) of the last RS codeword is calculated:K2=max{[L2−(depth−1)×M]/depth, 0}=max{[24−(4−1)×8]/4, 0}=max{0,0}=0. Thelength (K1=K11=K12) of the remaining RS codewords is calculated:K1=(L2−K2)/(depth−1)=(24−0)/(4−1)=8. This is illustrated in FIG. 12B.

The i=depth−1 column of the outer interleaver is a shortened RS (K2+2×t,K2, t=4) code. The i=0, 1, . . . depth −2 column of the outerinterleaver is a shortened RS (K1+2×t, K2, t=4) code. The bytes ofb(depth−1, K2+2×t+1), . . . , b(depth−1, K1+2×t) are padded with zeroes.A shortened block interleaver for RS(K1+2×t, K2, t=4) is used similar asin the scheme 4 example. FIG. 12B shows that 8 bytes of zeros are paddedto the last codeword and 8 bytes of tail bits are added to the lastcodeword, and 8 bytes of parity bits are added to each of the first tothird codewords. In this example, the shortened outer interleaver hasthe size of 4×16 bytes as shown in FIG. 12B which provides asignificantly higher efficiency compared to the outer interleaver havingthe size of 4×224 bytes.

In another embodiment, the information bytes can be padded further tomeet other system requirements, for example, the bit interleaverrequirement. The method of encoding the information bytes together withthe padded bits follows the same as described above.

According to at least one embodiment, the method of encoding theinformation bits is intended to meet the RS codeword boundary, the blockouter interleaver boundary and OFDM symbol boundary. Different schemesare provided which give different tradeoffs between simplicity and RScodeword performance, and the padding efficiency. At least oneembodiment of the invention provides much more efficient padding schemeswhile improving the decoding performance. Furthermore, at least oneembodiment of the invention does not require changes to current designs,either. At least one embodiment of the invention can be applicable toother wireless telecommunication standards such as IEEE 802.15.3c.

While the above description has pointed out novel features of theinvention as applied to various embodiments, the skilled person willunderstand that various omissions, substitutions, and changes in theform and details of the device or process illustrated may be madewithout departing from the scope of the invention. For example, althoughembodiments of the invention have been described with reference touncompressed video data, those embodiments can be applied to compressedvideo data as well.

Therefore, the scope of the invention is defined by the appended claimsrather than the foregoing description. All variations coming within themeaning and range of equivalency of the claims are embraced within theirscope.

1. A method of processing high definition video data to be transmittedover a wireless medium, the method comprising: in a physical layer,receiving an information packet having the length of L bytes, whereinL=(M×n×K)+A, and where: M is the depth of an interleaver, n is thenumber of interleavers, K is an encoding code length and A is the numberof remainder bytes with respect to M×n×K bytes, wherein the remainderbytes are located at the end of the information packet, and whereinM×n×K bytes represent M×n codewords; and converting the A remainderbytes into a plurality of shortened codewords, wherein each of theshortened codewords is shorter in length than each of the M×n codewords.2. The method of claim 1, wherein the plurality of shortened codewordshave a last codeword which is shorter than the remaining shortenedcodewords.
 3. The method of claim 2, wherein the last codeword is 8bytes shorter than the remaining shortened codewords.
 4. The method ofclaim 1, wherein the plurality of shortened codewords have the samecodeword in length.
 5. The method of claim 1, further comprising: outerencoding the M×n codewords and the plurality of shortened codewordsbased on the code length (K); outer interleaving the M×n codewords andthe plurality of outer encoded shortened codewords; inner encoding theouter interleaved codewords; and multiplexing the inner encoded data. 6.The method of claim 5, further comprising padding zeros to the innerencoded data so as to meet a predefined size requirement for the outerinterleaver.
 7. The method of claim 6, further comprising adding tailbits to the last codeword so that the length of the last codeword is thesame as those of the remaining shortened codewords.
 8. The method ofclaim 5, wherein the outer encoding comprises Reed Solomon (RS) encodingand the inner encoding comprises convolutional encoding.
 9. The methodof claim 8, further comprising padding zeros to the convolutionalencoded data such that the convolutional encoded data has an integernumber of orthogonal frequency division multiplexing (OFDM) symbols. 10.The method of claim 1, further comprising shortening the size of theouter interleaver for the remainder bytes in proportion to theshortening of the codewords.
 11. A system for processing high definitionvideo data to be transmitted over a wireless medium, the systemcomprising: a first module configured to receive an information packethaving the length of L bytes, wherein L=(M×n×K)+A, and where: M is thedepth of an interleaver, n is the number of interleavers, K is anencoding code length and A is the number of remainder bytes with respectto M×n×K bytes, wherein the remainder bytes are located at the end ofthe information packet, and wherein M×n×K bytes represent M×n codewords;a second module configured to convert the A remainder bytes into aplurality of shortened codewords, wherein each of the shortenedcodewords is shorter in length than each of the M×n codewords; and aprocessor cooperatively arranged with the first and second modules so asto process the bytes accordingly.
 12. The system of claim 11, whereinthe first module is configured to add tail bits to the last codeword sothat the length of the last codeword is the same as those of theremaining shortened codewords.
 13. The system of claim 11, furthercomprising: an outer interleaver configured to outer interleave the M×ncodewords and the plurality of RS encoded shortened codewords with thetail bits added; an inner encoder configured to inner encode the outerinterleaved codewords; and a multiplexer configured to multiplex theinner encoded data.
 14. The system of claim 13, wherein the outerinterleaver comprises: a first plurality of sub-outer interleaversconfigured to outer interleave the M×n codewords, respectively; and asecond sub-outer interleaver configured to outer interleave theplurality of RS encoded shortened codewords, wherein the size of thesecond sub-outer interleaver is significantly less than that of each ofthe first plurality of sub-outer interleavers.
 15. The system of claim14, wherein the size of the second sub-outer interleaver is 4×(K1+2t),where K1=ceil (A/4) and t is error correction capability (bytes).
 16. Amethod of processing high definition video data to be transmitted over awireless medium, the method comprising: a hardware processor coupledwith at least one outer interleaver, wherein each of the at least oneouter interleaver has a depth of M, and wherein the depth represents thenumber of columns of each outer interleaver; receiving an informationpacket having the length of L bytes, wherein L=(M×n×K)+A, wherein n=0,1, 2, 3, . . . and n represents the number of the at least one outerinterleaver, wherein K represents an Reed Solomon (RS) code length,wherein A=1, 2, 3, . . . K−1 and A represents the number of remainderbytes with respect to M×n×K bytes, wherein the remainder bytes arelocated at the end of the information packet, and wherein M×n×K bytesrepresent M×n codewords; converting the A remainder bytes into fourshortened codewords, wherein each of the shortened codewords is shorterin length than each of the M×n codewords, wherein the four shortenedcodewords comprise a last codeword, and wherein the last codeword is 8bytes shorter in length than the remaining three shortened codewords; RSencoding the plurality of shortened codewords based on the RS codelength (K); adding tail bits to the last codeword so that the length ofthe last codeword is the same as those of the remaining shortenedcodewords; and outer interleaving the plurality of RS encoded shortenedcodewords with the tail bits added.
 17. The method of claim 16, furthercomprising: outer interleaving the M×n codewords; and convolutionalencoding the outer interleaved M×n codewords and shortened codewords.18. The method of claim 17, further comprising padding zeros to theconvolutional encoded data such that the convolutional encoded data hasan integer number of orthogonal frequency division multiplexing (OFDM)symbols.
 19. The method of claim 17, further comprising: multiplexingthe convolutional encoded data; and padding zeros to the multiplexeddata so as to meet a predefined size requirement for a bit interleaver.20. The method of claim 19, wherein M=4 and K=216 and wherein the RSencoding comprises: determining an RS code parameter (K2) for the lastcodeword, wherein K2=max (floor (L′−24/4), 0), and wherein L′=L−floor(L/864)×864; determining an RS code parameter (K12) for the thirdcodeword, wherein K12=floor ((L′−K2)/3); determining an RS codeparameter (K11) for the first and second codewords, wherein K11=ceil((L′−K2)/3); RS encoding the first and second shortened codewords withan RS code (K11+2t, K11, t); RS encoding the third shortened codewordwith an RS code (K12+2t, K12, t); and RS encoding the last shortenedcodeword with an RS code (K2+2t, K2, t).
 21. A system for processinghigh definition video data to be transmitted over a wireless medium, thesystem comprising: at least one first outer interleaver, wherein each ofthe at least one first outer interleaver has a depth of M, and whereinthe depth represents the number of columns of each outer interleaver; afirst module configured to receive an information packet having thelength of L bytes, wherein L=(M×n×K)+A, wherein n=0, 1, 2, 3, . . . andn represents the number of the at least one first outer interleaver,wherein K represents an Reed Solomon (RS) code length, wherein A=1, 2,3, . . . K−1 and A represents the number of remainder bytes with respectto M×n×K bytes, wherein the remainder bytes are located at the end ofthe information packet, and wherein M×n×K bytes represent M×n codewords;a second module configured to convert the A remainder bytes into fourshortened codewords, wherein each of the shortened codewords is shorterin length than each of the M×n codewords, wherein the four shortenedcodewords comprise a last codeword, and wherein the last codeword is 8bytes shorter in length than the remaining three shortened codewords; anRS encoder configured to RS encode the plurality of shortened codewordsbased on the RS code length (K); a third module configured to add tailbits to the last codeword so that the length of the last codeword is thesame as those of the remaining shortened codewords; a second outerinterleaver configured to outer interleave the plurality of RS encodedshortened codewords with the tail bits added; and a processorcooperatively arranged with the first, second and third modules so as toprocess the bytes accordingly.
 22. The system of claim 21, wherein thefirst and second modules are integrated into the RS encoder.
 23. Thesystem of claim 21, wherein the third module is integrated into thesecond outer interleaver.
 24. The system of claim 21, wherein the RSencoder is further configured to: determine an RS code parameter (K2)for the last codeword, wherein K2=max (floor (L′−24/4), 0), and whereinL′=L−floor (L/864)×864; determine an RS code parameter (K12) for thethird codeword, wherein K12=floor ((L′−K2)/3); determine an RS codeparameter (K11) for the first and second codewords, wherein K11=ceil((L′−K2)/3); RS encode the first and second shortened codewords with anRS code (K11+2t, K11, t); RS encode the third shortened codeword with anRS code (K12+2t, K12, t); and RS encode the last shortened codeword withan RS code (K2+2t, K2, t).
 25. A system for processing high definitionvideo data to be transmitted over a wireless medium, the systemcomprising: means for receiving an information packet having the lengthof L bytes, wherein L=(M×n×K)+A, and where: M is the depth of aninterleaver, n is the number of interleavers, K is an encoding codelength and A is the number of remainder bytes with respect to M×n×Kbytes, wherein the remainder bytes are located at the end of theinformation packet, and wherein M×n×K bytes represent M×n codewords; andmeans for converting the A remainder bytes into a plurality of shortenedcodewords, wherein each of the shortened codewords is shorter in lengththan each of the M×n codewords.